Head injuries cause vital brain tissue losses

Toronto, March 4 (IANS) A Canadian study has found that the degree of severity of traumatic brain injury (TBI) causes a proportional loss of its tissue, particularly white matter. “This is an important finding as TBI is one of the most common forms of disability,” said Brian Levine of Baycrest’s Rotman Research Institute and co-author of the study, published in the latest issue of the journal Neurology.

TBI causes both localised damage through bruises or bleeds, as well as more diffuse damage through disconnection of brain cells, which ultimately causes cell death.

“The localised damage is easier to detect with the naked eye than diffuse damage. Yet both kinds of damage contribute to difficulties with concentration, working memory, organising and skills required for holding onto a job and mood changes often experienced by people following TBI.

“It can be hard to determine why patients are so disabled, and this study offers a clue to the nature of the brain damage causing this disability,” said Levine.

In the study, 69 TBI patients were recruited from Sunnybrook Health Sciences Centre, Canada’s largest trauma centre, one year after injury.

Eighty percent had sustained injuries from road accidents. The severity was determined by the depth of coma or consciousness alteration at the time of the initial hospitalisation.

Subjects’ brains were scanned with MRI. In addition to using an expert radiologist’s qualitative reading of the MRI scans, researchers processed the images with a computer programme that quantified volumes in 38 brain regions.

The computerised analysis revealed widespread brain tissue loss that was closely related to the severity of the TBI sustained one year earlier.

“Brain tissue loss was greatest in the white matter,” Levine said.

Investigators were surprised to find that volume loss was widespread even in TBI patients who had no obvious lesions on their MRI scans.

“A significant blow to the head causing loss of consciousness can cause extensive reduction of brain tissue volume that may evade detection by traditional qualitative radiological examination,” Levine noted.